The International Space Station is nearing completion, and with the looming demise of the Space Shuttle program and significant gap before the next-gen Constellation-class rocket is available, a replacement set of launchers is needed. And that's why NASA has had to outsource supply missions to the ISS in the interim period.

What's interesting is NASA's choice of supplier. Two contracts, for $1.6 billion and $1.9 billion, have gone to Space Exploration Technologies (SpaceX) and Orbital Sciences Corp. respectively, both relatively small private companies. SpaceX and Orbital, along with Russian spacecraft which will deal with human spaceflight, will supply the ISS with cargo between 2010 and 2016.

Orbital's eight launches will be from NASA’s Wallops Island launch pads, while SpaceX's twelve will rocket from the Kennedy Space Centre. In total 40 tons of pressurized and unpressurized cargo will be lifted to the ISS in orbit, amounting to about 70% of the ISS cargo requirements from 2013 onwards.

A separate, failed, bid for the work came from PlanetSpace, which is an alliance between Boeing, Lockheed Martin and Alliant Techsystems: all huge players in the high-tech manufacturing area, and with experience in space technology.

SpaceX and Orbital have developed their systems privately, with SpaceX achieving the historic position of being the "first privately financed company to achieve orbit with a liquid-fueled rocket" in September of this year with the successful launch of the small Falcon1 rocket. The video below shows its flawless 10-minute ride into orbit, after a few previous failed launch attempts.